CoastCoastCue field guide
Why the water can be higher than the tide table said
A tide prediction models astronomical forcing. The coast experiences weather and water movement on top of that predictable signal, so an observation can be correct even when it differs from the table.
Wind moves water
Persistent onshore wind can pile water against the coast, while offshore wind can lower it. The effect depends on shoreline shape, water depth, duration, and the size of the connected water body. A short wind reading does not explain every anomaly, but a sustained pattern can shift the whole curve.
Pressure changes sea level
Lower atmospheric pressure allows the water surface to rise and higher pressure tends to suppress it. The response is not identical everywhere, and it combines with wind rather than acting alone.
Rain and river flow matter
At river mouths and estuaries, runoff and upstream discharge can raise water levels or change current strength without changing the astronomical tide prediction. Local drainage and flood-control operations can add another layer.
Compare like with like
First verify the station, datum, unit, and timestamp. Then check whether one value is Observed and the other Predicted. CoastCue's anomaly view compares those labels directly when NOAA provides a suitable live sensor. It is context for planning, not a flood forecast or safety warning.